Effect of operator experience level on clinical outcomes of indirect- and direct-bonding techniques: A single-center, open-label, quasi-randomized controlled clinical trial

Objective: This study aimed to compare the clinical outcomes of indirect- and direct-bonding techniques for bracket placement in orthodontic treatment, focusing on the influence of operator experience. Methods: A total of 153 patients were quasi-randomly assigned to the indirect- or direct-bonding group, of whom 124 were analyzed. Clinical outcomes in the two groups were compared and further stratified by operator experience (1-3 years vs. 4-6 years). The evaluated parameters included total treatment duration, chair time, discomfort during bonding (visual analogue scale scores), plaque control record, bracket failures, intentional reattachments, and post-treatment occlusal index (CR-Eval scores). Results: In procedures performed by operators with 1-3 years of experience, the indirect-bonding group demonstrated significantly shorter treatment duration, shorter chair time, fewer intentional reattachments, and better post-treatment occlusal outcomes than the direct-bonding group. However, bracket failure rates were significantly higher in the indirect-bonding group, regardless of operator experience. In procedures performed by operators with 4-6 years of experience, most parameters showed no significant intergroup differences. Conclusions: The indirect-bonding technique improved treatment efficiency and quality, with potential advantages for less-experienced operators. However, attention to technique is essential to minimize bracket failures. These findings support the incorporation of indirect bonding in clinical training programs.